Use existing color variables

Author: haslinghuis

src/css/tabs/configuration.less

@@ -143,8 +143,8 @@
         .btn {
             padding: 0.15rem 0.5rem;
             font-size: 10px;
-            border: 1px solid #ccc;
-            background: #f5f5f5;
+            border: 1px solid var(--surface-400);
+            background: var(--primary-300);
             cursor: pointer;
             border-radius: 999px;
             white-space: nowrap;
@@ -156,12 +156,12 @@
                 background-color 200ms;
 
             &:hover {
-                background: #e9e9e9;
-                border-color: #999;
+                background: var(--primary-500);
+                border-color: var(--surface-500);
             }
 
             &:active {
-                background: #ddd;
+                background: var(--surface-300);
             }
         }
     }